This disclosure generally relates to ceramic materials. More particularly, it relates to nanoscale ordered composites of ceramic materials produced through block copolymer assisted assembly.
Composite materials having long-range order exist in nature. Natural composites, such as seashells, exhibit extraordinary mechanical properties that stem from the unique hierarchically ordered structure in these materials. This realization has triggered an effort to mimic nature by building long-range ordered structures at the nanoscale level. Order on the nanoscale can be used, in turn, as the first step towards hierarchically ordered structures ranging from nanometer to micrometer to millimeter scales.
The technology to produce nanoscale inorganic ordered structures includes “top-down” approaches (e.g., sequential deposition and nanolithography) and “bottom-up” approaches (e.g., self-assembly based on ionic and nonionic surfactants and block copolymers). Inorganic ceramic materials, such as silica and other oxides having nanoscale order, have been obtained by self-assembly using organic species as structure-directing agents. Polymeric precursors have been used to develop fibers, coatings, bulk ceramics, nanotubes and nanofibers of boron nitride, boron carbide, silicon nitride and silicon carbide, and to fabricate high temperature micro-electromechanical systems (MEMS) with dimensions in the micron to sub-millimeter range.
Current synthetic techniques such as the self-assembly approach have not yielded hierarchically ordered ceramic materials with nanoscale features suitable for high temperature applications. There accordingly remains a need for hierarchically ordered ceramic materials with nanoscale dimensions, and methods for making such materials, that are stable at high temperatures.